84 SUPPLEMENT TO THE CRAG MOLLUSC A. 



The little recent shell from the British seas, Trochus pusilla, is given by Dr. P. 

 Carpenter as a synonym to Margarita Vahlii ; the young state of M. trochoidea from the 

 Crag could scarcely be separated from it. 



Margarita argentata ? Gould. Supplement, Tab. V, fig. 12. 



Margarita argentata, Gould. Invertebrata Mass., p 256, fig. 174. 



Locality. Chillesford bed, Aldeby. 



In a packet of shells found at Aldeby, and obligingly sent to me by Messrs. Crowfoot 

 and Dowson, was the small and not quite perfect specimen figured as above. It is a 

 young individual, and very distinctly striated all over, and I have (but with doubt) 

 referred it to Marg. argentata, Gould. It has a small apex, differing in that respect from 

 M. trochoidea of ' Crag Moll/ 



Length, O'l. 



Mr. Jeffreys has, in vol. v, ' Brit. Conch.,' p. 202, given argentata as a synonym of 

 Margarita glauca, Moller, ' Ind. Moll. Groenl./ p. 8. The specimen now figured is more 

 coasely striated than the representation of Trochus glaucus in ' Brit. Conch.,' vol. v, PI. 

 CI, fig. 6. Gould speaks of his shell as " composed of four convex whorls, the last of 

 which is slightly angular." His figure does not show this angularity, but it is perceptible 

 in the Crag shell. 



Adeorbis pulchralis, 8. Wood. Crag Moll., vol. i, p. 139, Tab. XV, fig. 4. 



In the ' Quart. Journ. Geol. Soc.,' vol. xxvii, p. 495, it is said by Mr. Jeffreys, 

 " Adeorbis pulchralis. Swedish expedition, 320 — 600 fathoms. Margarita trochoidea, 

 S. Wood, is the same species." On a re-examination of my specimens I still believe they 

 are distinct. 



Adeorbis striatus, Phil. Crag Moll., vol. i, p. 137, Tab. XV, fig. 7 (as Adeorbis 



strialus, S. Wood.) 



Locality. As in Crag Moll. only. 



In 'Brit. Conch.,' vol. iii, p. 315, Adeorbis striatus, A. supranilidus, and A. tricari- 

 natus are considered as varieties of a British shell called there Trochus Duminyi, Requien. 

 A specimen from the Oligocene of Cassel sent me by Dr. von Koenen, with the name 

 carinatus attached, approaches as near, or even nearer, to the three Crag species as 

 (judging from Mr. Jeffreys' figure and description) does the recent Duminyi. While 



